Centralise packet handling for common packets  … (#111)
Centralise packet handling for common packets  … (#111)

* Centralise packet handling for common packets

Updates #84, #95, #96

* use sendError

ScriptRock/sftp,fuchsia-mirror/third_party-pkg-sftp,pkg/sftp,fuchsia-mirror/third_party-github.com-pkg-sftp,akupas/sftp